Stabilizer fin control system for a towed buoy

ABSTRACT

A mechanical load sensing arrangement is disposed at the buoy tow point and is coupled to the tow cable. This load sensing arrangement is mechanically displaced proportional to tensile loading of the cable. A mechanical stabilizer fin attitude control arrangement is interconnected between the stabilizer fin and the load sensing arrangement. The attitude control arrangement is responsive to the mechanical displacement of the load sensing arrangement to control the stabilizer fin to assume a low-lift attitude when the tensile loading exceeds a first given amount and to assume a normal lift attitude when the tensile loading is less than a second given amount, where the second given amount is less than the first given amount.

li 253. OR 3.906.883 SR United States Patent 1191 1111 s, u6,66sMajkrzak Sept. 23, 1975 STABILIZER FIN CONTROL SYSTEM FOR A TOWED BUOYPrimary ExaminerTrygve M. Blix Assistant ExaminerSherman D. Basinger[75] Inventor. ghjarles Peter Ma krzak, Nutley, Anomey, Agent or FirmJOhn T UHaHoram Menotti J. Lombardi, Jr.; Alfred C. Hill [73] Assignee:International Telephone and Telegraph Corporation, Nutley, NJ. [57]ABSTRACT [22] Filed: 22 1974 A mechanical load sensing arrangement isdisposed at the buoy tow point and is coupled to the tow cable. PP441,692 This load sensing arrangement is mechanically displacedproportional to tensile loading of the cable. A

52 U.S. c1 114/235 B meenanieel Stabilizer fin attitude eennolarrangement 51 1111. c1. B63B 21/56 is interconnected between theStabilizer fin and the 5 Field f Search u 114/235 R, 235 B, 236; loadsensing arrangement. The attitude control ar- 74/469 470 rangement isresponsive to the mechanical displacement of the load sensingarrangement to control the [56] References Cited stabilizer fin toassume a low-lift attitude when the UNITED STATES PATENTS tensileloading exceeds a first given amount and to assume a normal liftattitude when the tensile loading is 2,945,469 7 1960 Pu1s1fer 114/235 Bless than a Second given amount, where the Second 22m 2: 3 given amountis less than the first given amount.

3,618,555 11/1971 Kelly et a1. 114/235 B 9 Claims, 5 Drawing FiguresOCQLE as} US Patent se t.23,1975 SW20 3,906,883

H34 oomu 3 o US Patent Sept. 23,1975 Sheet 3 of3 3,906,883

.l i mmd 000m HMDJOOOm x mm 00 mm mm y mY NWM U STABILIZER FIN CONTROLSYSTEM FOR A TOWEI) BUOY BACKGROUND OF THE INVENTION This inventionrelates to submarine antenna buoys and more particularly to anarrangement associated with the buoy to prevent cable rupture.

During tow by a submarine, the tensile loading within the tow cable isnormally greater at the buoy tow point than at the tow winch aboard thesubmarine. To prevent loss of a buoy through cable rupture by excessiveloading before such loading can be sensed and compensation for at thewinch, a load sensing arrangement needs to be incorporated at the towpoint to instantaneously sense local cable tension. Excessive cable loadcan than be relieved by decreasing the demand for lift by the buoy.

In normal use, the buoy is towed in a defined normal attitude to producea normal lift. When cable tension exceeds 5,000 pounds, as it may inhigh velocity tow or with abnormal transient conditions, this attitudemust be altered to a low-lift condition to relieve cable tension. Thisis accomplished through the use of a trimming stabilizer fin within thebuoys horizontal hydrofoil. When tow velocity or abnormal cable load isdecreased to below 2,500 pounds, the trimming stabilizer fin readjustsso as to return the buoys attitude to normal lift.

Stabilization can be achieved by sensing cable loads directly at the towpoint of the buoy where such loads are maximum. In the past this hasbeen accomplished by employing an electrical sensing and servo-operatedstabilizing system with a strain-gage-type sensor at the tow point. Thishas an advantage of enabling a control of the buoy's attitude frominboard the submarines. However, such an electrical arrangement requirestransmission of large amounts of electrical power in the tow cable,results in source of electrical noise which could cause static in theradio frequency signals received by an antenna contained in the buoy andis rather complex and, thus, the reliability of the electrical system isreduced.

SUMMARY OF THE INVENTION An object of the present invention is toprovide a mechanical control system in the buoy to control the attitudeof the stabilizer fin.

Another object of the present invention is to provide a mechanicalcontrol system for the stabilizer fin of a towed buoy which minimizestransmission of electrical power in the tow cable, eliminates a sourceof electrical noise and increases reliability through simplicity.

A feature of the present invention is the provision of a stabilizer fincontrol system for a towed hollow buoy comprising: a tow cable for thebuoy; a stabilizer fin for the buoy; a first mechanical means disposedat the buoy coupled to the cable, the first means being mechanicallydisplaced proportional to tensile loading of the cable; and a secondmechanical means interconnected between the stabilizer fin and the firstmeans, the second means being responsive to the mechanical displacementof the first means to control the stabilizer fin to assume a low-liftattitude when the tensile loading exceeds a first given amount and toassume a normal lift attitude when the tensile loading is less than asecond given amount, the first given amount being greater than thesecond given amount.

BRIEF DESCRIPTION OF THE DRAWING bilizer fin attitude controlarrangement in its'flipping position with impending flip of thestabilizer fin from its normal lift position to its low-lift position;

FIG. 4 is a schematic diagram of the mechanical stabilizer fin attitudecontrol arrangement in its flipped position with the stabilizer fin inits low-lift position; and

FIG. 5 is a schematic diagram of the mechanical stabilizer fin attitudecontrol arrangement in its re-flipping position with the stabilizer finin an impending flip from its low-lift position to normal lift position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, there isillustrated schematically a stabilizer fin control system for a towedhollow buoy in accordance with the principles of the present invention.The control system includes a mechanical load sensing arrangement 1disposed at the buoy coupled to tow cable 2 with arrangement 1 beingmechanically displaced proportional to the tensile loading of cable 2and a mechanical stabilizer fin attitude control arrangement 3interconnected between stabilizer fin 4 and arrangement l witharrangement 3 being responsive to the mechanical displacement ofarrangement 1 to control stabilizer fin 4 to assume a low-lift attitudewhen the tensile loading of cable 2 exceeds a first given amount and toassume a normal lift attitude when the tensile loading of cable 2 isless than a second given amount, where the first given amount is greaterthan the second given amount. I

Cable 2 includes internally thereof electrical cable 5 to supplyelectrical power to electrical apparatus contained within the buoy, suchas the winch motor employed to control the erection and retraction of acommunication antenna contained within the buoy.

Stabilizer fin 4 is in practice actually formed in two sections, onesection being disposed in the buoys horizontal hydrofoil on one side ofthe buoy and the other section being disposed in the buoys horizontalhydrofoil on the other side of the buoy, with these two sections of thestabilizer fin being interconnected by a connecting rod upon whicharrangement 3 operates to simultaneously control the two sections toassume the same attitude.

Arrangement 1 includes a hollow cylindrical'member i 6 having alongitudinal axis and a pair of slots 7 and 8 parallel to thelongitudinal axis and diametrically opposite each' other with member 6being connected to the outer surface of the buoy adjacent the tow point.Arrangement 1 also includes a housing 9 connected to the inner surfaceof the buoy disposed coaxially of an extension of the longitudinal axisof member 6. Member FIG. 3 is a schematic diagram of the mechanical sta-6 and housing 9 may be connected to the appropriate location of the buoyhull 10 by providing a flange 11 on member 6 and a flange 12 on housing9 with each of these flanges 11 and 12 having apertures therein alignedwith each other and aperatures in the hull 10. The aperatures in flange12 are tapped to receive bolts 13 so as to enable the connection ofmember 6 and housing 9 to hull 10 at the tow point.

Arrangement 1 further includes a cylindrical element 14 disposed withinmember 6 coaxial of its longitudinal axis in a longitudinal slidingrelationship with the interior of member 6. Element 14 includes a pairof projections 15 and 16 adjacent the upper end of element 14diametrically opposite each other. Projections l5 and 16 slideablyengage an associated one of slots 7 and 8 to permit displacement ofelement 14 when tow cable 2 is under a load. Electro-mechanical planarclevis 17 connects the lower end of element 14 to cable 2. An invertedcup-shaped member 18 having a bottom 19 is slideably disposed in housing9 coaxial of the extension of the longitudinal axis of member 6. Amechanical load displacement device 20 is disposed within inverted cupmember 18 between bottom 19 and a wall 21 adjacent the inner surface ofthe buoy. Tie bar 22 is connected to the upper end of element 14 andextends through hull 10 of the buoy, through the load displacementdevice 20 and beyond the bottom 19 of inverted cup-shaped member 18coaxial of the longitudinal axis of member 6 and the extension of thisaxis. Bar 22 is fastened to bottom 19, such as by nut 23, so that bottom19 and, hence, the cup-shaped member 18 may be displaced downward whenthe load increases on cable 2. An arm 24 is connected to bar 22 adjacentthe end that extends beyond bottom 19 of the inverted cupshaped member18 with this arm carrying actuator 25 in the form of a pin.

Arrangement 3 includes a link 26 having an elongated slot 27 adjacentthe upper end thereof into which actuator 25 is slideably received. Aspring-loaded snap toggle 28 has one end thereof pivotably connected tothe lower end of link 26 and its other end connected to a mechanicalpush-pull cable 29. Pushpull cable 29 includes an outer metallic sleeve30 with the ends thereof being secured against physical motion in buoypartitions 31 and 32, respectively, and a mechanically moveable member33 contained within the outer sleeve 30. This element 33 will be pushedor pulled in response to toggle 28. End 34 of element 33 is pivotablyconnected to the other end of toggle 28 while end 35 of member 33 isconnected to link 36 having an elongated slot 37 substantiallythroughout its length. Follower 38 is slideably received in slot 37 andresponds to motion of link 36 so that spring-loaded snap toggle 39 cancontrol the attitude of stabilizer fin 4. Spring 40 of toggle 39 willmaintain stabilizer fin 4 in either of the two attitudes it is caused toassume by arrangement 3. The attitude assumed will be dependent upon thetensile loading of cable 2.

The force from loaded tow cable 2 produces a proportional deflection ofdevice 20 and, hence, actuator 25 which is transmitted through link 26,toggle 28, push-pull cable 29, link 36 and toggle 39 to stabilizer fin4. The mechanical load displacement device 20 may be any of severaldifferent types of load displacement components, such as a coil spring,a captive mass of rubber with proper bulk modulus of compression orBelleville springs. By way of example device 20 containing 35 Bellevillespring units of lnconel X at 2 inch diameter and 0.058 inches thick andoperating at a maximum stress of 100,000 pounds per square inch at flatloading will displace actuator 25 to a practical length to 0.575 inchesat a 5,000 pound load.

Referring to FIGS. 2-5 the operation of arrangement 3 for various loadconditions will now be discussed.

When the cable load is transferred through device 20, actuator 25 moveswithin slot 27 of link 26 connected to toggle 28 so that at 2,500 poundsactuator 25 is at the bottom of slot 27 and no effective transfer ofload has been made to toggle 28 until the 2,500 pounds of cable load isexceeded. At this point actuator 25 begins to transfer load through link26 to toggle 28. A further increase in load will actuate toggle 28 fromits normal position of FIG. 2 to a flipping position for toggle 28 asillustrated in FIG. 3. It will be noted in FIG. 2 that follower 38 is inthe approximate center of slot 37 and link 36 is in its retractedposition and stabilizer fin 4 is in its normal lift attitude. In theflipping position of FIG. 3 follower 38 is at the bottom of slot 37 withlink 36 in its mean position and stabilizer fin 4 in an impending flipcondition from a normal lift position to a low-lift position. When theload increases beyond 5,000 pounds toggle 28 flips to its second stableposition and toggle 39 flips to its second stable position. When toggle39 flips to its second stable position, stabilizer fin 4 is flipped to alow-lift attitude as illustrated in FIG. 4. It will be noted in FIG. 4that actuator 25 is at the top of slot 27 and that link 36 is in itsextended position with follower 38 approximately in the center of slot37. During this sequence of operation as illustrated in FIGS. 2, 3 and4, stabilizer fin 4 has remained in a normal trim position and wascaused to flip into and held at a low-lift position when toggles 28 and39 were flipped.

As the cable tension or load is reduced from 5,000 pounds, toggle 28moves toward its re-flipping position until the 2,500 pound level isreached and toggle 28 is in its re-flipping position as illustrated inFIG. 5. As illustrated in FIG. 5 actuator 25 is at the top of slot 27and toggle 28 has moved into its re-flipping position while link 36 hasbeen pulled by push-pull cable 39 to its mean position and follower 38is at the top of slot 37. A decrease of the load below 2,500 poundscauses actuator 25 to flip toggle 28 into the position illustrated inFIG. 2 which will cause link 36 to pull follower 38 down through meansof push-pull cable 29. When link 36 reaches its retracted positiontoggle 39 will cause stabilizer fin 4 to flip to its normal liftattitude as illustrated in FIG. 2.

In the above sequence of operation there is a stepped control of thestabilizer fin 4 at 5,000 pounds and 2,500 pounds. The control system ofthis invention, however, is also readily capable to automaticallyprovide continual attitude control over the cable-load range. Thiscontinual attitude control is accomplished by replacing the controlslots in links 26 and 36 with pin joints.

While I have described above the principles of my invention inconnection with specific apparatus it is to be clearly understood thatthis description is made only by way of example and not as a limitationto the scope of my invention as set forth in the objects thereof and inthe accompanying claims.

I claim:

wabiliae fimcqn l .sy e .fQr at me imllgw b u oy comprisingz 5 secondmechanical means interconnected between said stabilizer fin and saidfirst means, said second means being responsive to the mechanicaldisplacement of said first means to control said stabilizer fin toassume a low-lift attitude when said tensile loading exceeds a firstgiven amount and to assume a normal lift attitude when said tensileloading is less than a second given amount, said first given amountbeing greater than said second given amount;

said first means including a hollow cylindrical member having alongitudinal axis and a pair of elongated slots parallel to said axisand diametrically opposite each other, said cylindrical member beingconnected to the outer surface of said buoy adjacent a tow point,

a cylindrical element disposed within said cylindrical member coaxial ofsaid axis in a longitudinal sliding relation with said cylindricalmember, said cylindrical element having a pair of projections adjacentone end thereof diametrically opposite each other, each of said pair ofprojections slideably engaging a different one of said pair of slots,

a planar clevis connecting the other end of said cylindrical element tosaid cable,

a cylindrical housing connected to the inner surface of said buoydisposed coaxial to an extension of said axis,

an inverted cup-shaped member slideably disposed in said housing coaxialof said extension of said axis,

a mechanical load displacement device disposed within said invertedcup-shaped member between the bottom thereof and the inner surface ofsaid buoy,

a bar connected to said one end of said cylindrical element extendingthrough a wall of said buoy, through said load displacement device andbeyond the bottom of said inverted cup-shaped member coaxial of saidaxis and said extension of said axis, said bar being secured to thebottom of said cup-shaped member,

an arm connected to said bar adjacent the end thereof that extendsbeyond the bottom of said inverted cup-shaped member, and

an actuator carried by said arm to control said second means.

2. A control system according to claim 1, wherein said load displacementdevice includes a resilient member.

3. A control system according to claim 2, wherein said resilient memberincludes a captive rubber member.

4. A control system according to claim 2, wherein said resilient memberincludes a coil spring.

5. A control system according to claim 2, wherein said resilient memberincludes Belleville springs.

6. A control system according to claim 1, wherein said second meansincludes a first link having an elongated slot adjacent one end thereofinto which said actuator is slideably received,

a first snap toggle having one end thereof pivotably connected to theother end of said first link,

a mechanical push-pull cable having each end thereof mounted to apartition within said buoy, one end of said push-pull cable beingpivotably connected to the other end of said first toggle,

a second link having an elongated slot substantially throughout itslength, said second link being connected to the other end of saidpush-pull cable,

a follower slideably received in said elongated slot of said secondlink, and

a second snap toggle connected between said follower and said stabilizerfin.

7. A control system according to claim 6, wherein said second toggleincludes a spring having one end connected to a fixed point and theother end connected to said stabilizer fin to maintain said stabilizerfin in either of its assumed attitudes.

8. A stabilizer fin control systemfor a towed hollow buoy comprising: i

a tow cable for said buoy;

a stabilizer fin for said buoy;

a first mechanical means disposed at said buoy coupled to said cable,said first means being mechanically displaced proportional to tensileloading of said cable; and q a second mechanical means interconnectedbetween said stabilizer fin and said first means, said second meansbeing responsive to the mechanical displacement of said first means tocontrol said stabilizer fin to assume a low-lift attitude when saidtensile loading exceeds a first given amount and to assume a normal liftattitude when said tensile loading is less than a second given amount,said first given amount being greater than said second given amount;

said second means including a first link having an elongated slotadjacent one end thereof into which an actuator controlled by said firstmeans is slideably received,

a first snap toggle having one end thereof pivotably connected to theother end of said first link,

a mechanical push-pull cable having each end thereof mounted to apartition within said buoy, one end of said push-pull cable beingpivotably connected to the other end of said first toggle,

a second link having an elongated slot substantially throughout itslength, said second link being connected to the other end of saidpush-pull cable,

a follower slideably received in said elongated slot of said secondlink, and

a second snap toggle connected between said follower and said stabilizerfin.

9. A control system according to claim 8, wherein said second toggleincludes a spring having one end connected to a fixed point and theother end connected to said stabilizer fin to maintain said stabilizerfin in either of its assumed attitudes.

1. A stabilizer fin control system for a towed hollow buoy comprising: atow cable for said buoy; a stabilizer fin for said buoy; a firstmechanical means disposed at said buoy coupled to said cable, said firstmeans being mechanically displaced proportional to tensile loading ofsaid cable; and a second mechanical means interconnected between saidstabilizer fin and said first means, said second means being responsiveto the mechanical displacement of said first means to control saidstabilizer fin to assume a low-lift attitude when said tensile loadingexceeds a first given amount and to assume a normal lift attitude whensaid tensile loading is less than a second given amount, said firstgiven amount being greater than said second given amount; said firstmeans including a hollow cylindrical member having a longitudinal axisand a pair of elongated slots parallel to said axis and diametricallyopposite each other, said cylindrical member being connected to theouter surface of said buoy adjacent a tow point, a cylindrical elementdisposed within said cylindrical member coaxial of said axis in Alongitudinal sliding relation with said cylindrical member, saidcylindrical element having a pair of projections adjacent one endthereof diametrically opposite each other, each of said pair ofprojections slideably engaging a different one of said pair of slots, aplanar clevis connecting the other end of said cylindrical element tosaid cable, a cylindrical housing connected to the inner surface of saidbuoy disposed coaxial to an extension of said axis, an invertedcup-shaped member slideably disposed in said housing coaxial of saidextension of said axis, a mechanical load displacement device disposedwithin said inverted cup-shaped member between the bottom thereof andthe inner surface of said buoy, a bar connected to said one end of saidcylindrical element extending through a wall of said buoy, through saidload displacement device and beyond the bottom of said invertedcup-shaped member coaxial of said axis and said extension of said axis,said bar being secured to the bottom of said cupshaped member, an armconnected to said bar adjacent the end thereof that extends beyond thebottom of said inverted cup-shaped member, and an actuator carried bysaid arm to control said second means.
 2. A control system according toclaim 1, wherein said load displacement device includes a resilientmember.
 3. A control system according to claim 2, wherein said resilientmember includes a captive rubber member.
 4. A control system accordingto claim 2, wherein said resilient member includes a coil spring.
 5. Acontrol system according to claim 2, wherein said resilient memberincludes Belleville springs.
 6. A control system according to claim 1,wherein said second means includes a first link having an elongated slotadjacent one end thereof into which said actuator is slideably received,a first snap toggle having one end thereof pivotably connected to theother end of said first link, a mechanical push-pull cable having eachend thereof mounted to a partition within said buoy, one end of saidpush-pull cable being pivotably connected to the other end of said firsttoggle, a second link having an elongated slot substantially throughoutits length, said second link being connected to the other end of saidpush-pull cable, a follower slideably received in said elongated slot ofsaid second link, and a second snap toggle connected between saidfollower and said stabilizer fin.
 7. A control system according to claim6, wherein said second toggle includes a spring having one end connectedto a fixed point and the other end connected to said stabilizer fin tomaintain said stabilizer fin in either of its assumed attitudes.
 8. Astabilizer fin control system for a towed hollow buoy comprising: a towcable for said buoy; a stabilizer fin for said buoy; a first mechanicalmeans disposed at said buoy coupled to said cable, said first meansbeing mechanically displaced proportional to tensile loading of saidcable; and a second mechanical means interconnected between saidstabilizer fin and said first means, said second means being responsiveto the mechanical displacement of said first means to control saidstabilizer fin to assume a low-lift attitude when said tensile loadingexceeds a first given amount and to assume a normal lift attitude whensaid tensile loading is less than a second given amount, said firstgiven amount being greater than said second given amount; said secondmeans including a first link having an elongated slot adjacent one endthereof into which an actuator controlled by said first means isslideably received, a first snap toggle having one end thereof pivotablyconnected to the other end of said first link, a mechanical push-pullcable having each end thereof mounted to a partition within said buoy,one end of said push-pull cable being pivotably connected to the otherend of said first toggle, a seCond link having an elongated slotsubstantially throughout its length, said second link being connected tothe other end of said push-pull cable, a follower slideably received insaid elongated slot of said second link, and a second snap toggleconnected between said follower and said stabilizer fin.
 9. A controlsystem according to claim 8, wherein said second toggle includes aspring having one end connected to a fixed point and the other endconnected to said stabilizer fin to maintain said stabilizer fin ineither of its assumed attitudes.